48 two groups. The data was computed through the statistical package for social
sciences SPSS version 17.0.
9. Testing Hypothesis
After analyzing the data, the researcher tested the hypothesis.
3.7 Instrument of the Research
The instrument for collecting the data was objective vocabulary test. The
instrument was held for pretest and posttest. Pretest was applied before the treatment in order to identify how far the students’ achievement in vocabulary
related to content words concrete noun and verb with title kinds of jobs, and posttest was applied after presenting the treatment in order to identify the
improvement of students’ vocabulary achievement related to content words Kinds of jobs. The test was in the form of multiple choice tests. The items of
pretest and posttest were the same. It was based on the result of try out test. The Test evaluated the meaning of vocabulary. The vocabulary that was included in
the test was related to content words. The validity of the test concerned with the content and constructs validity.
3.8 Try Out Test
Try out was held in different class from the sample classes. The purpose of administering try out was to prove whether the test has good validity, reliability,
discrimination power and level of difficulty. So, the try out of the test here was to determine whether the items can be used as pretest and posttest. The numbers of
49 items in this try out were 50 items which were in multiple choice forms. The test
was given to the try out class before the pretests in experimental class and control class were administered.
After that, the result of try out test showed which items that could be taken as
pretest and posttest, because those items were included into the criteria of good test.
The items which did not fulfill the criteria of the good test, those would not be
used for pretest and posttest. The try out was conducted in 90 minutes.
3.9 Criteria of Good Test
In this research, to prove whether the test had good ability, it would be tried out
first. The test could be said have a good quality if it has a good validity, reliability, level of difficulty, and discrimination power. The try out test was given to the
students to know how the quality of the test which was used as the instrument of the research. The try out test was given to another class that was not included in
the sample. The data gained were analyzed to judge the level of difficulty, discrimination power, validity, and reliability of the test.
1. The Validity of the Tests
According to Heaton 1991:159 states that the validity of the test is the extent to
which is measured whether the test has a good ability. There are 5 validity, those are: face validity, content validity, predictive validity, construct validity. In order
50 to measure whether the test have good validity, the researcher analyzed the test
from content validity and construct validity.
a. Content Validity
According to Heaton 1991:160 the test should be constructed as to contain a
representative sample of the course. It means that the tests should represent the materials that have been taught to the students. This research applied one material
for the treatments. The test should represented those materials. To know whether the test has a good content validity the items of the test. In the content validity,
the materials were given which suitable with the curriculum. To fulfill this validity, the researcher saw all the indicators of the instrument and analyzed them
whether the instrument had represented the material that would be measured or not.
The researcher used the table of specification to check content validity of the test
items. Gronlund 1981:101 stated that table of specification was to illustrate how such table was used to check on content validity.
If the table represented the material that the tester wanted to test, it meant that it
was a valid test from the point of view Shohamy, 1985:74.
51 The content of try out was presented in the table of specification below:
Table I. Table of Specification of the Try out Test
No Word Classes
Vocabulary Number of items
Percentage 1
Concrete Nouns Postman, cheerleader,
attendant, painter, typist, hairdresser, radio mechanic,
nurse, bank clerk, mechanic, butcher, dentist, custom officer,
stewardess, farmer, factory worker, teacher, carpenter,
fisherman, actress, waiter, judge, firefighter, referee,
doctor, architect, shop assistant, tailor, florist, astronaut,
journalist, lawyer, headmaster, soldier, bookseller.
1., 2., 3., 4., 5., 7., 8., 10., 11., 13., 14., 17.,
18., 19., 20., 22., 25., 27., 28., 30., 32., 33.,
34., 35., 36., 37., 38., 39., 40., 41., 42., 43.,
44., 46., 47., 50 72
2 Verbs
Study, work, dance, drive, sing, watch, teach, clean, cook, play,
sail, sell, drink, water 6., 9., 12., 15., 16.,
21., 23., 24., 26., 29., 31., 45., 48., 49
28 Total
100
b. Construct Validity Construct validity was focused on the kind of test that was used to measure the
ability. According to Setiyadi 2006:26 if the instrument just measure one aspect, for example vocabulary, the construct validity can be measured by evaluate all
items in the test. If all items have measured vocabulary mastery, the instrument has fulfilled construct validity.
c. Reliability
Kategori